gistfile1.scala

Welcome to Scala version 2.11.4 (OpenJDK 64-Bit Server VM, Java 1.7.0_71).
Type in expressions to have them evaluated.
Type :help for more information.

scala> :paste
// Entering paste mode (ctrl-D to finish)

object A { sealed trait B ; case object C extends B }
import A._
class A(val b: B)

// Exiting paste mode, now interpreting.

defined object A
import A._
defined class A

scala> :reset
Resetting interpreter state.
Forgetting all expression results and named terms: $intp, A
Forgetting defined types: A

scala> :paste
// Entering paste mode (ctrl-D to finish)

object A { sealed trait B ; case object C extends B }
import A._
class A(val b: B = C)

// Exiting paste mode, now interpreting.

<console>:9: error: not found: type B
       class A(val b: B = C)
                      ^
<console>:9: error: not found: value C
       class A(val b: B = C)
                          ^

scala> :paste
// Entering paste mode (ctrl-D to finish)

object A { sealed trait B ; case object C extends B }
import A._
class A(val b: A.B = A.C)

// Exiting paste mode, now interpreting.

defined object A
import A._
defined class A